CONCLUSIONS 



Sea water at depths of 2,500 and 6,000 feet in the Pacific Ocean 

 is more aggressive to aluminum alloys than is sea water at the surface. 



Aluminum alloys, because of their susceptibility to pitting and 

 crevice types of corrosion must be protected for sea water applications 

 if reasonable service life is desired. In general, aluminum alloys 

 would not be recommended for deep sea applications for periods longer 

 than three years if protective maintenance cannot be performed. 



Copper base alloys which are susceptible to dezincif ication and 

 dealuminif ication are not recommended for sea water service. The other 

 copper base alloys corroded uniformly and can be used in sea water 

 service where their corrosion rates can be tolerated. 



The nickel base alloys which were uncorroded can be used in sea 

 water applications where their mechanical and physical properties ful- 

 fill the other requirements. 



Because of the susceptibility of the other nickel base alloys to 

 crevice corrosion, their use in sea water applications would not be 

 recommended unless adequate precautions were taken to prevent this 

 type of attack. 



Steels, cast irons and austenitic cast irons because of their uni- 

 form corrosion can be used for sea water applications especially if 

 adequate protective measures are employed. 



The stainless steels because of their proneness to crevice cor- 

 rosion and different manifestations of pitting are not recommended for 

 sea water applications. 



Titanium alloys, except welded 13V-llCr-3Al alloy, are recommended 

 for sea water applications. 



The iron-nickel-chromium-molybdenum alloys, columbium, tantalum 

 and Ta-60 alloy are recommended for sea water service. 



Molybdenum, tungsten, chemical lead, antimonial lead and tellurium 

 lead, because of their low uniform corrosion, can be used in some sea 

 water applications. 



Tin, zinc and lead-tin solder are not recommended for sea water 

 service. Zinc is used as a sacrificial anode when it is desired to use 

 it to protect more noble alloys. 



Magnesium alloy AZ31B is unsatisfactory for sea water applications. 



Because of crevice corrosion, iron-nickel-chromium alloys are not 

 recommended for sea water service. 



12 



